In this book a number of ideas and results related to the ?eld of cybern- ical physics – the scienti?c area aimed at the study of physical systems by cybernetical means – are presented. Although some publications in physical journals related to control problems appeared long ago, formation of a se- rateself-sustainedareastartedaslateasinthe1990sduetotheexplosion-like developmentofresearchincontrolofchaos,quantumcontrol,andotherareas. The number of publications has reached several thousands by the end of the century and it continues to grow very rapidly. This book is, perhaps, the ?rst attempt to present a uni?ed exposition of the subject and methodology of cybernetical physics as well as solutions to some of its problems. A part of this book presents the limits of system transformation by means of control both for conservative and for dissipative systems based on Hamiltonian description of system dynamics. A survey of various control applications in physics is given: control of chaos, controlled synchronization, control of spatiotemporal systems, control ofmolecularandquantumsystems.Anapproachforbuildingmodelsofsystem dynamics based on control methods is discussed. The presented methods and results are illustrated by examples of new approaches to classical problems: Stephenson–Kapitsa pendulum, escape from a potential well, synchronization of coupled oscillators, control of chemical reaction with phase transition, c- trolled dissociation of molecules, controlled oscillations of complex crystalline lattices. Controlled pendulums appear in many parts of the book since p- dulum models can be thought of as the “atoms of nonlinear physics”.